Some signal conversion systems use In-phase/Quadrature (I/Q) configurations, in which a complex digital signal is represented by orthogonal I and Q components. In some I/Q configurations, a complex digital signal is converted into an analog signal using a pair of Digital-to-Analog Converters (DACs), one for converting the I component and the other for converting the Q component. Such configurations are used, for example, in communication transmitters.
Some transmitters pre-distort the complex digital signal before digital-to-analog conversion, e.g., in order to compensate for non-linear distortion caused by the transmitter Power Amplifier (PA).